“Day of the Doctor” promises several Time Lords sure to be a’leaping through time and space. Matt Smith stars as the current Eleventh Doctor, with David Tennant revisiting the pinstripes and trainers for another go as the Tenth Doctor. John Hurt also stars, just for timey-wimey fun/confusion. The 75-minute special also features Jenna Coleman, who plays the current Doctor’s current companion, and Billie Piper, best known for riding shotgun on the TARDIS during Tennant’s run.